Ryan Manufacturing, Box 239, Newark, Ill. 60541 and Hiniker Company, P.O. Box 3407, Mankato, Minn. 56001 have made spray shields used in spray shield assemblies that were adapted to be attached to a frame moved over the crops or plants and that were adapted to have attached to them liquid distribution means including an inlet adapted to be coupled to a source of liquid under pressure (e.g., a liquid pumping system on a tractor to which the frame is attached), two or three liquid outlet nozzles, and means (e.g., hoses and hose connectors) for distributing liquid from the inlet to the outlet nozzles. Such spray shields have been made of a polymeric material or metal and have defined channels each opening through one side and front and rear axially spaced ends so that crops or plants can be temporarily positioned within the channel as the spray shield is moved over them.
U.S. Pat. No. 4,947,581 describes a spray shield assembly that provides adjustment to adapt the location of the liquid spray sources within the spray shield to the size or shape of the crops being sprayed. That spray shield assembly includes a polymeric spray shield (e.g., a spin or rotary molding of polyethylene) including a leading portion that converges axially from adjacent the front end toward the rear end of the spray shield to, if necessary, help direct or funnel portions of plants into a channel the spray shield defines, and a semi cylindrical portion extending from the end of the converging leading portion opposite the front end of the spray shield toward the rear end of the spray shield. The semi cylindrical portion has spaced opposite side parts joined by a central top part adapted to have means for suspending the spray shield from a support frame attached thereto, and has spaced generally parallel edges that help define the open side of the channel. Each of the side parts has an array of through openings with the openings in each array each disposed at a different distance from the adjacent edge, and means are provided for mounting a nozzle assembly in one of the through openings in each of the arrays to position nozzles in those assemblies with their outlet ends projecting from the inner surface of the spray shield to direct spray from the nozzles in generally opposite directions at desired locations and orientations relative to the edges and thereby to the plants along the rows. The top part also has an opening through which the third outlet nozzle assembly is mounted so that it projects from the inner surface of the spray shield and directs spray in generally at a right angle to the opposite directions in which spray from the nozzles in the side parts are directed, and the arrays and the central opening are spaced axially from each other along the longitudinal axis of the spray shield to restrict interference between liquid spray being discharged from the nozzles.
While the arrays of openings in the spray shield described in U.S. Pat. No. 4,947,581 advantageously afforded a variety of positions for the liquid spray sprayed into the spray shield, the axial orientations of the nozzles along the arrays are more dictated by the arcuate shape of the side parts than may be desired.